from The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide

Major rock-fill dam across the Nile near Aswan, Egypt. It is 111 m/364 ft high and 3,600 m/11,815 ft long, with a volume of 42,600,000 cubic metres/55,809,000 cubic yards. Financed by the USSR, construction of the dam began in 1960 and was completed in 1970. It keeps the level of the Nile constant throughout the year without flooding. The dam has the capacity to generate 2,100 megawatts of electricity.

The dam impounds Lake Nasser, its reservoir, which extends for about 560 km/348 mi behind it. Construction of the dam enabled the Nile's annual flood waters to be controlled for the first time, and made water available for irrigation and for industrial and domestic purposes. It has also improved navigation above and below Aswan, while generating large amounts of electricity. The agricultural area has been increased by 20%.

The creation of Lake Nasser necessitated the relocation of 90,000 Egyptians and Sudanese Nubian nomads. Ancient monuments were also moved to avoid their submersion, notably the Abu Simbel temple which was moved 60 m/197 ft above its original site, and the Philae temple to the higher-lying island of Agilka.

History of the dams The first Aswan Dam, 2 km/1.2 mi long and 54 m/177 ft high, was built in 1902 and is situated 6 km/4 mi downstream from the Aswan High Dam. Water for irrigation can be released from the lake behind the older dam at the rate of 1.5 million litres per second. The construction of the Aswan High Dam formed part of a major water resource project aimed at providing irrigation water, domestic and industrial water, hydroelectric power generation, and flood control. Funds for the scheme were originally to have come from the USA, but the withdrawal of the offer in 1956 led to the nationalization by Egypt of the Suez Canal and the invasion of Egypt by British, French, and Israeli forces. The USSR eventually agreed to finance the High Dam project, and by a treaty signed in 1959 it was agreed that Sudan should receive new water rights and be paid compensation for the parts of the Nile Valley within the valley to be flooded by the new reservoir.

Environmental impact The construction of the dam led to the absence of silt in the Lower Nile Valley, which increased the erosive power of the river and damaged the Nile and eastern Mediterranean fisheries by reducing the supply of nutrients. There is also considerable water seepage and evaporation loss from Lake Nasser. Moreover, it appears that the disease bilharzia is spreading more rapidly with the increase in irrigation and the building of new canal systems.